Thoughts on Landing Pages as Validation?

In the past, many startups validated their business by throwing a simple landing page online. I’m talking about 2006-2017. To me it seems that nowadays this would in most instances not work. With the amount of websites existing and Google results dominance I feel that a landing page alone wouldn’t validate much. For example Flexport. Founder put up a landing page with I believe some Google Adwords and had great results. What do you think?